Economy of scale

General tips / questions on seeding & planting

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Allan
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There is a little piece of mathematical logic which is worth understanding if you wish to make the
most of economy of scale.
Suppose you are building up a compost bin of panels which we will make of unit width, say 1 metre
wide. Four of these will make an enclosure of size 1x1+ 1 square metre. Now the next season you
want to enlarge so you get another 4 panels and make a second bin, also1 square metre. Then you
start to think, suppose I put the two sets together, how big is the bin, the answer is 2x2=4 square
metres, that is twice as much. you can go on enlarhing, a third set gives you3x3=9 square metres. In other words it depends on the square of the multiplication factor. This logic applies of course to anything similar such as edging a deep bed or erecting a wire fence to keep rabbits out, there is a big economy of scale. There is a slight improvement to be made also from making a polygon out of the units. I suggest you look at an octagon and work out its size compared to the 2x2 square which you can easily do by breaking it up into triangles, rectangles and a square.
Not so obvious perhaps, if you wanted to put slug pellets around a crop, putting them around each plant is going to need far more than putting a barrier round the whole area.
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Johnboy
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Well forgive me Allan but I fail to see your logic and I would suggest you check your mathmatics.
Apart from the fact that compost is worked out by using Cubic Capacity so you are a dimension missing!
Decicedly!!
JB.
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richard p
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Location: Somerset UK

surely with the bigger compost bin you would be able to hump it up a lot in the middle so get even more in! as with a lot of things big is beautiful, before anyone starts i said big not enormous,:D
Chris
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Hi

I see the mathematial logic re. square meters per panel - but panels are cheap and I find my three separate 1m cubed bins much more practical. (In this area we can also get plastic compost bins from the Council for a tenner - so I've also got 2 of those plus a leafmold bin and a long term compost heap for all the stuff I don't want to put in the bins).

Chris
Chris
Allan
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Location: Hereford

Johnboy,
I'm sorry you don't understand the logic. I tried to keep it simple but seem to have failed to help you.
The assumption was made for the compost bin that height was constant, thus what goes for the area
advantage would apply to the volume advantage. In other words you multiply both areas by a factor of 1 to produce volume figures .
Regarding whether one wants to use a small or big bin I have no difficulty in getting the 8 panel bin
to compost, it actually works better than the 4 panel one, less drying out and a higher temperature but it doesn't pay to go even bigger as there is insufficient air gets to the middle. One can overcome this by various means such as a central ventilator, in practice I don't bother.
The actual figure for the octagon works out as 4.82 times the volume of the single sided small bin.If
you don't know how to get there, subdivide the octagon into 9 parts with parallel lines horizontally and vertically. You then have a square of unit area, 4 triangles added together to make another square of unit size and 4 rectangles each of area 1/(root2).
4x1/(root2)=4x(root2)/2=2x(root2)=2.82. Total=4.82

To help you,Google has inbuilt calculator, thus
http://www.google.co.uk/help/features.html#calculator
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Johnboy
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Hi Allan,
Poor simple me but when I went to school
1M x 1M = 1 Sq. Metre then build another alongside and you have 2 sq. Metres and another alongside and you have 3 sq. Metres yet somehow you have managed to get 4 and 9 respectively.
When dealing with compost bins you want to know how much compost you are making so a third dimension is needed. If the material was 1M Long x .15M wide and you then made your box up the calculation would be
1M x 1M x .15M then you would have .15 Cubic Metres
make another box and you have .3 Cubic Metres and a third you would have .45 Cubic Meters. To me this is logic and I have read and reread your posting and
I fail to see any of it as logic.
If you do not see what I mean please mail me direct.
JB.
Allan
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Location: Hereford

To keep it simple let's just assume unit height when going from area to volume, so the figures are identical.
I am not talking about adding areas.My argument is concerned with what happens to the area when you double the circumference.In your example you are in effect putting 2 complete 4-panel bins side by side and why not if that's what you want, but if they are touching then you have in effect two panels in the middle that aren't doing any good at all so you might as well take them out of the middle and add one to each end making a 2 x 2 square bin. so you have 2 panels each way in a bigger square You now have not 2 but 4 square metres.
The same thing occurs if you think about circles
We have there
circumference =PI x diameter or PI x2x radius
but area =PI x {radius)squared
so we get the results
radius circimference(x2 xPI) area(xPI)
1 1 1
2 2 2x2=4
3 3 3x3=9
4 4 4x4=16
and so on

Does this help?
Allan
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Apology. In the table the silly machine has squashed all my spacings out. It is meant to be 3 columns with headings, not a glorious sandwich.
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arthur e
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sorry Allan but non of your maths past 1+1=1 works.
to make a 2cubic mt box you only need 6 panels, a 3cubic mt needs 8 panels, you only need 2 extra panels for each extra cubic mt. try laying out matches to see how it works.
arthur e
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You are talking about strict rectangular boxes, not polygons. That's a totally different thing. I use mesh panels wired together so that beyond the basic 4 to make a square box it is a polygon not a rectangle. At the moment I have 8 regular octagons erected and in various states of composting, there are no retaining posts.
I can see that if you want individual bins of unit volume you would put them side by side, that's not what I am talking about.
Mr Potato Head

Code: Select all

X----X----X----X----X
|    |    |    |    |
|    |    |    |    |
X----X----X----X----X

versus

X----X----X
|    |    |
|    |    |
X----X----X
|    |    |
|    |    |
X----X----X


The top example uses 10 posts (X's) 13 sides and provides 4 compost bins the same size as the bottom example which uses 9 posts and 12 sides...
Jim

At the risk of extending this extremely tedious argument beyond everyone's endurance, I'd just like to point out that area is measured in square metres (even when it's the area contained by a shape other than a square) whereas volume is measured in cubic metres. I never knew anyone who just lays out their compost flat on the groun - so volume it is, then. Therefore the contents of your bin should be expressed in cubic metres (or feet if you're more comfortable with Imperial measurements).
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richard p
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Location: Somerset UK

thanks guys it is just like the old forum after all !!!!!
Guest

If you take example 2 of your diagram and take out the inner walls you have the sort of bin I was talking about. I use linked panels with no posts. So you have twice the circumference but 4 times the volume. If you then re-shape it to an octogon it becomes 4.82 times as big as the small bin.
I was trying to illustrate in the simplest way I know that the cost of one shape of container per unit area or volume is better for larger containers than small ones.
It's as if you went into a shop for a pack of 4 items and were told that if you buy 2 packs you get 2.8 extra packs free.
Youm might not want that extra but it's worth considering it.
Note to Jim. By assuming unit height the arithmetic for areas is exatly the same as for volumes. This has already been mentioned.
Jim

The arithmetic is not the problem. Any maths teacher could tell you that you don't express volume in square metres, but cubic. Sliding away from that fact doesn't actually negate it. :roll:
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